Effect of butan-1-ol on autoignition characteristics of ammonia

• Ignition delay times (IDTs) of NH 3 /butan-1-ol/O 2 /Ar blends. • Investigation on the effect of butan-1-ol on ignition behaviors of ammonia. • Investigation on the effect of pressure on the shortening-rate. • Investigation on the effect of equivalence ratio on the shortening-rate. To investigate the effect of butan-1-ol (n-butyl alcohol, NBA) on autoignition characteristics of ammonia (NH 3 ), ignition delay times (IDTs) of NH 3 /butan-1-ol/O 2 /Ar blends with butan-1-ol mole fractions of 0 %, 5 %, 10 %, and 30 % were measured behind reflected shock waves over a range of experimental conditions: 1100–2000 K, around 0.14 MPa and 0.5 MPa, and equivalence ratios of 0.5, 1.0 and 2.0. It is observed that a tendency of crossover for the IDT in the high-temperature range is observed between the blend containing 30 % butan-1-ol and other blends. Except for the blend containing 30 % butan-1-ol, when the equivalence ratio is 1.0, increasing the pressure ( p ) to 0.5 MPa, over the experimental temperature range, the IDT of the blends is shortened and the shortening-rate is reduced as compared to that under a pressure of 0.14 MPa. Butan-1-ol has been demonstrated to have the strongest ignition-promoting effect under oxygen-enriched conditions, particularly for the blend containing 5 % butan-1-ol. Increasing the butan-1-ol mole fraction makes the sensitivity of the IDT of blends to the equivalent ratio becoming strong at first and then weak.